1. Field of the Invention
The present invention relates to semiconductor devices and methods of making semiconductor devices.
2. Description of the Related Art
Packaged semiconductor devices called SON (Small Outline Non-leaded Package) or QFN (Quad Flat Non Leaded Package) have been widely manufactured. FIG. 32 shows a QFN semiconductor device in a sectional view (see JPA-2009-246395). The semiconductor device X in FIG. 32 includes a resin case 91, a base lead 92, a semiconductor chip 93, lead terminals 94, and connection wires 95. The semiconductor chip 93 is fixed to the base lead 92, and is connected with the lead terminals 94 via the connection wires 95. The semiconductor device X as described above is manufactured by using a lead frame. The lead frame is a metal plate having a thickness of about 0.2 mm, formed into a desired pattern by e.g., precision punching or etching.
When manufacturing the semiconductor device X using a lead frame, a semiconductor chip 93 is placed on a base lead 92, then the semiconductor chip 93 is connected with lead terminals 94 by connection wires 95, and the lead frame is covered with a resin case 91. Thereafter, unnecessary portions of the lead frame are cut and removed.
For producing small electronic devices, the semiconductor device X is also subjected to size reduction and increased functionality. One way to reduce the size is to reduce the thickness of the semiconductor device X. In making a thinner semiconductor device X, the thicknesses of the base lead 92 and the lead terminals 94 can be a disadvantage. To address this, proposals have been made for manufacturing packaged semiconductor devices without using a lead frame. For this, terminals may be made on a metal base by plating, and then the base may be removed by etching.
However, when the terminals are formed not by using a lead frame but by plating as described above, the terminals will have a thickness of about 20 μm, and may readily be pulled out of the resin case. Thus, it is necessary to ensure great pull-out resistance of the terminals in manufacturing semiconductor devices without using lead frames.